Sensitive photographic material



Noms, 1935. SESHEPPARD Em 2,019,137

SENSITIVE PHOTOGRAPHIG MATERIAL Filed May 1e, 1954 Sms/rive LAYER lNcLuDm AN ORTno-Ansfmre (CADMIUM, MERcumc, Mfncvnus, NlcKELous, Saver?, Fmuous, TuomuM OR Smlvmc.)

" ff ya Z Patented Nov. 5, 1935 Samuel A E. Sheppard Rochester, N. Y., assi New York and Waldemar Vanselow, gnors to Eastman Kodak Company, Rochester, N. Y.,

a corporation of Application May 18, 1934, Serial No. 726,348

5 Claims.

'I'his invention relates to photographic elements and particularly to suchelements containing in a suitable colloid carrier certain ortho-arsenites as light-sensitive compounds.

It has been known that certain aresenitesiiave light sensitive properties and hypothetical or prophetic statements have appeared in the literature implying that arsenitesin general have light-sensitive properties.

We have conducted extensive investigations with these compounds and we have been able to discover such properties in only a. few and these 'do not constitute a group that can be exclusively or accurately classified by any familiar classification according to their chemical structures. We have discovered that certain metal ortho-arsenites do have useful 'photo-sensitive properties, yielding either a visible image on exposure, particularly to ultra-violet light, or being photo thermographic, or both, and this application relates to this group as hereafter exactly dened.

The term photothermographic is herein used as defined in our application, Serial No.v 501,663, led December 11, 1930, matured into Patent No. 1,976,302, to denote the property oi a material, after exposure to light, of decomposition or modiilcation under the inuence of. heat differentially in accordance with the exposure.

In general the photographie element comprises a colloid carrier containing the metal ortho-arsenite and coated upon a suitable support such as metal, glass or paper. The colloid carrier may be gelatine but when the heat necessary to develop an image is high a colloid capable of withstanding it must be used, such as a condensation product of formaldehyde land phenol. (A well knownproduct of this type is sold under the trade-mark Bakelite and has been found satisfactory.) y

The properties and method of preparation of the particular compounds found to be useful will now be specifically described.

1. Cadmium ortho-arsenite, Cds(AsO:) a, is white in color and is obtained by adding a solution of cadmium nitrate to an excess of the potassium ortho-arsenite. Cadmium-ortho-arsenite yields print-out images after exposure to .ultra-violet light. It does not show photothermographic properties at low temperatures but does when heated over a Bunsen burner.

2. Mercurio ortho-arsenite, Hga(AsOa)z, is white and is obtained when a solution of mercurio nitrate is added to one of potassium orthoarsenite.

3. Mercurous ortho-arsenite, HgaASOs, is yelof an excess of potassium ortho-arsenite with a low in color and is prepared according to a method given in Melloijs Inorganic Chemistry, Vol. 1X, p. 127. It is prepared by adding a solution ot arsenic trioxide in 50% alcohol to an aqueous solution of mercurous nitrate acidiiled with a few drops of nitric acid; and mixed with alcohol until it just begins to appear turbid. The product can be dried at C. The mercurio and mercurous ortho-arsenites yield print-out images alter exposure to ultra-violet light but have only slight photothermographic properties at C. or at higher temperatures.

4. Nckelous ortho-arsenite, NisUisOa) z. is green in color and was prepared by treating a solution l5 solution of nickelous nitrate.' This has slight photothermographic properties only when sub-4 mitted to high temperatures, as over a Bunsen burner.

5. Silver ortho-arsenite, AgaASOa, is yellow and 2o was obtained by adding equivalent amount 'of aqueous silver nitrate to anaqueous solution of sodium arsenite, NaaHiisOn This has by far the most pronounced photosensitive properties, yield,- ing a visible image readily on exposure to ultraviolet light and exhibiting photothermographic properties at relatively low temperature, as well as at elevated temperaturen.

6. Stannlo ortho-arsenite, Sn3(AsOa) 4.5-1/2 H20 may be obtained by adding an aqueous solution of arsenic trioxlde to an aqueous solution of stannic acid containing about an equal amount of sodium chloride. The compound is white in color. This exhibits photothermographic properties at 200 C.

'IJIhalious ortho-arsenite, 'I'l3AsO:, is yellow. In this case aslight excess of thallous nitrate in water was added to an aqueous solution of potassium ortho-arsenite. This yields a visible image on exposure to ultra-violet light and exhibits only 4o slight photothermographic properties and only at a high temperature.

8. Thorium ortho-arsenite, TimAsOa) 4, is cbtained by adding a slight excess of thorium nitrate to potassium ortho-arsenite. The product 45 is white. This exhibits only slight'photothermographic properties and then only at a high cases the powder may be sprinkled uniformly over asuitable base, such asglass, whichhas been rreshlycoatedwithacarriersuchasbakelite. In certain cases, ior example, with silver or thallous ortho-arsenite, the mixture may be prepared by precipitation in a gelatin solution as in the preparation of silver halide emulsions.1 t

It is further to be noted that, while the eight salts noted have sensitive properties to a extent, only iive are sensititveto ultra-violet light.

In the accompanying drawing is shown on an enlarged scale in section a photographic element having a support I, and sensitive layer 2 including one of the salts mentioned.

Having thus described our invention, what we claim as new and desire to be secured by Letters Patent of the United States is:

1. A photographic material comprising a colloid carrier and a light sensitive material therein, the light sensitive material being one of the .iollowing metal ortho-arsenites: cadmium, mercuric, mercurous, nickelous, silver, thallous, tetravalentthoriumandstannic. i"

2. A photographie material capable oi yielding a visible image upon exposure to ultra-violet light and comprising a colloid carrier and a light sensitive material therein, the light sensitive material being one oi the following metal ortho-arsenites: cadmium, mercurio, mercurous, silver and thalious. f f f 3. A photographic element comprising a support and a sensitive layer thereon, the sensitive layer comprising a colloid carrier and a light 1o sensitive material therein, the iight sensitive material being one oi the following metal ortho-arsenites: cadmium, mercurio, mercurous, nickelous, silver, thallous, tetravalent thorium and stannic. l

4.. A photographic element comprising a support and a sensitive layer thereon, the layer comprising a colloid carrier and silver ortho-arsenite.

5. A photograhic material comprising a colloid carrier and silver ortho-arsenite.

l SAMUEL E.SHEPPARD.

WALDEIIAR VANSELOW. 

